A friend asked Dr. Wang that the asymptomatic period of AIDS can be as long as 20 years, so how do you know if you are infected?
The subject is to confuse the concept of incubation period and window period, but this is also a problem that many friends are easy to confuse.
This article will make several AIDS-related concepts clear at once:
First of all, the window period refers to the time after the virus enters the human body until the corresponding infection marker can be detected. Therefore, the window period is mainly related to the diagnosis of the disease. During the window period, it is like a window obscuring the virus, so that people cannot know the existence of the virus, so it is figuratively called the window period. For HIV, the test markers are mainly nucleic acids, antigens and antibodies.
Why is there a window period? Because after the virus enters the human body, it takes a certain amount of time to replicate and multiply to a sufficient amount, at which time the viral nucleic acid can be detected by experimental instruments. And all quantitative detection instruments, there are problems with detection sensitivity, which is why when we look at the virus detection report, some write less than 20, some write less than 50, some write less than 100 and so on. Even if the detected person has a disease load of 0, limited to the sensitivity of the instrument, the detection report will be reported according to the standards of the instrument calibration, written less than 20, less than 50, less than 100, and so on.
After a period of time, the virus stimulates the body to produce antigenic substances to reach a detectable amount, and finally the antibodies that react to the antigen reach a detectable amount.
According to the latest diagnostic standards for HIV infection promulgated by the National Health Commission, according to the existing detection technology, the window period for detecting nucleic acids, antigens and antibodies is about one week, about two weeks and about three weeks respectively.
After talking about the window period, let's talk about the three concepts of the course of the disease, namely the acute stage, the asymptomatic infection period and the AIDS phase.
The acute phase usually occurs 2 to 4 weeks after HIV infection, and some infected people will experience transient fever, sore throat, lymphadenopathy, night sweats, fatigue, diarrhea and other symptoms, which generally last 1 to 3 weeks.
Friends often use these symptoms to ask Dr. Wang after dangerous behaviors, am I infected? Again, acute symptoms are not specific, that is, they are difficult to distinguish from the common cold, so no one can tell you whether you are infected through these symptoms, and the diagnosis of AIDS must have a laboratory test basis.
And to remind everyone, do not think that no symptoms are not infected, because some friends do not have these symptoms after infection, or the symptoms are mild and do not feel. Therefore, it is not possible to try to infer whether there is infection based on the presence or absence of symptoms, which is neither accurate nor scientifically based.
After the acute phase, it will enter the asymptomatic infection phase, when the patient does not have any externally recognizable signs and symptoms, but if not treated, the damage of the virus to the body will continue to exist, and the body's immunity will continue to decline.
When CD4+ T cells are below 200 or regardless of cd4+ T cell levels, opportunistic infections or even opportunistic tumors appear, the patient is considered to have entered the AIDS phase.
I have just explained the course staging in detail, and then the concept of incubation period. The incubation period refers to the period when the virus enters the human body to the appearance of disease-related signs and symptoms, and this time is as if the virus is lurking in the body, hidden under the iceberg, and does not cause visible signs and symptoms in the human body. The incubation period of different infected individuals is different, mainly related to the amount of virus infected, the type and virulence of the virus, and the immune status of the patient himself. As short as a few months, as long as more than a decade. The average incubation period calculated according to the population is not completely consistent in different studies, and it is generally believed that it can reach 8 to 10 years.
It can be seen that the window period is related to the diagnosis, and the incubation period is related to the presence of symptoms. The course of the disease is divided into acute phase, asymptomatic infection phase and AIDS phase. The time of the window period and the acute phase intersect, and the time of the incubation period covers the window phase, the acute phase, and the asymptomatic infection phase.